1. Field of the Invention
The present invention relates to a shutter driving apparatus for a photographic printer which is arranged such that the path of a ray of light which is incident on a photographic paper is opened and closed by rotating a shutter.
2. Description of the Related Art
In photographic printers for printing an image on a photographic paper, the path of a ray of light which is incident on a photographic paper is opened and closed by means of a shutter so that the photographic paper is exposed to light for a predetermined period of time to print an image thereon.
A shutter of this type is generally rotated or pivoted so as to open and close the path of a ray of light incident on the photographic paper. To drive the shutter, it is common practice to use an apparatus which employs either a rotary solenoid or a bipolar solenoid.
The shutter driving apparatus that employs a rotary solenoid is arranged such that the shutter is rotated from a position for opening the path of the incident light to a position for closing the same by means of driving force which is derived from the rotary solenoid when excited and the shutter is then returned to the light path opening position by the action of a spiral spring which is provided on the rotary solenoid.
In the shutter driving apparatus that employs a bipolar solenoid, the shutter is rotated from the light path opening position to the light path closing position by means of driving force which is derived from the bipolar solenoid when excited and the shutter is then returned to the light path opening position by reversing the polarity of the electric power supplied to the bipolar solenoid.
In shutter driving apparatuses of the types described above, stoppers are provided in addition to a solenoid such as a rotary solenoid or a bipolar solenoid so that the shutter abuts against each stopper when it is rotated to reach the light path opening or closing position.
Accordingly, every time the shutter abuts against one or the other of the two stoppers, a relatively great impact is generated, and this adversely affects the durability of the mechanism and also causes generation of noise.